In the presence of noncompact symmetry, the stability of relative equilibria under momentum-preserving perturbations does not generally imply robust stability under momentum-changing perturbations. For axisymmetric relative equilibria of Hamiltonian systems with Euclidean symmetry, we investigate different mechanisms of stability: stability by energy–momentum confinement, KAM, and Nekhoroshev s...

1. INTRODUCTION. There is obvious value in finding the most efficient ways to arrange objects like balls or polyhedra in a given container. There is more scope for rich mathematics in having the " container " be all of space, so there are no boundaries to spoil the potential symmetry of the optimal arrangements, and this is the type of problem we will consider (see Figure 1 for an efficient and...

We use boundary quantum group symmetry to obtain recursion formulas which determine nondiagonal solutions of the boundary Yang-Baxter equation (reflection equation) of the XXZ type for any spin j. Department of Mathematics, University of York, York YO10 5DD, U.K. Physics Department, P.O. Box 248046, University of Miami, Coral Gables, FL 33124 USA

The paper presents an outline for introduction of symmetry ideas and techniques for solution of partial differential equations into the curriculum for training of teachers of mathematics. The main goal of such special course would be integration of the previously gained knowledge in calculus, algebra and ordinary differential equations together with showing students some developments in modern ...

In this paper, by the method of moving planes, we prove the symmetry result which says that classical solutions of Monge-Ampere system in the whole plane are symmetric about some point. Our system under consideration comes from the differential geometry problem. Keyword: Moving plane, positive solutions, radial symmetric, MongeAmpere system Mathematics Subject Classification: 35J60, 53C21, 58J05

In this article we derive C -a priori estimates on the Riemann invariants of the Euler compressible equations in the case of cylindrical or spherical symmetry. These estimates allow then to construct shock waves with a time of existence proportional to the distance to the origin at the initial time. 2000 Mathematics Subject Classification: 35L60, 35Q31, 76N10.

In this article we derive C -a priori estimates on the Riemann invariants of the Euler compressible equations in the case of cylindrical or spherical symmetry. These estimates allow to construct shock waves with a time of existence proportional to the distance to the origin at the initial time. 2000 Mathematics Subject Classification: 35L60, 35Q31, 76N10.

In this paper, we propose a method based on GMM (the generalized method of moments) to estimate the parameters of stable distributions with 0 < α < 2. We don’t assume symmetry for stable distributions. AMS 2000 Mathematics Subject Classification: Primary 62H12; Secondary 62F12, 62H12